The present invention relates to packaging materials and in particular, to heat-sealable packages that are intended for anaerobic or vacuum packing of perishable foods and other products.
Preservation of food and food portions is important for a variety of economic, health, and convenience reasons. Food can be stored for longer periods of time if oxygen is excluded and the harmful effects of oxygen on food are minimized. Containers have long been used to store and transfer perishable foods and other products on their way to market for purchase by consumers. After perishable foods, such as meats, fruits, and vegetables are harvested, they may be placed into containers or atmospheres to protect them from the spoiling effects of oxygen. Containers are also used by retailers or by consumers to store and transport individual servings or left-over portions of food. In these instances, it may be even more useful to exclude oxygen and thus retard spoilage of the food item. Some solutions to these problems are outlined, for example, in U.S. Pat. No. 2,778,171.
The environment in which the food or food product is stored is probably the most important factor in preserving the food item. It is important to maintain proper temperatures, but the atmosphere in which the food product or other item is stored has the greatest effect on the preserved life of the product. By providing an appropriate atmosphere within the storage container, the food or other item can be better preserved when maintained at the proper temperature. A preservative atmosphere will also help when the item is exposed to variations in temperature, such as freezing and thawing, or when it is subjected to the temperature variations in a cargo hold, such as in an airplane or a ship. The molecular or atomic content of the gases in the atmosphere may be the single most important factor in the preservation process.
Maintaining low levels of oxygen is generally preferred because it is well known that the fresh quality of meats can be preserved longer under anaerobic conditions than under aerobic conditions with typical levels of oxygen. Maintaining low levels of oxygen minimizes the growth and multiplication of aerobic bacteria, and thus contributes to longer life of a food product, such as meats or cooked food items. Minimizing oxygen also retards oxidation generally, and can provide an ideal atmosphere for storing many other types of products subject to oxidation or corrosion.
These products may include electrical or electronic products. Items such as printed circuit boards, integrated circuits, or even passive items, such as resistors or capacitors, may have very fine copper traces that depend on preservation of the trace for proper functioning of the circuit. Corrosion and oxidation from even a xe2x80x9cnormalxe2x80x9d atmosphere may be damaging to such products, especially when combined with temperature variations, assembly operations, and contamination. In-process cleaning operations, combined with preservative techniques, may extend the performance and the life of such products and their higher assemblies.
What is needed is a packaging solution that eliminates oxygen from a storage environment, leaving the environment suitable for storage of food products, as well as other products, in an atmosphere that is largely free of oxygen. This solution should be cost-effective, as well as handy and convenient, and preferably available both to retailers and consumers.
One embodiment of the invention is a container comprising first and second panels, each panel defining inner and outer surfaces, said panels joined together to form a package for placing a product therein. Each of said first and second panels further comprises a first plurality of non-interconnected channels on an inner surface of said first panel. There is a second plurality of non-interconnected channels on an inner surface of the second panel, the second plurality different from the first plurality in at least one of orientation and extent, the first and second pluralities cooperating to form evacuation paths.
Another embodiment of the invention is a tubular element for forming a container. The tubular element comprises a first member formed from a gas-impermeable, heat-sealable material. There is a second member formed from a gas-impermeable, heat-sealable material. The first member is bonded to the second member along a first and a second side of said first and second members. There is a first plurality of non-interconnected channels on an inner surface of the first member and a second plurality of non-interconnected channels on an inner surface of the second member, said second plurality different from said first plurality in at least one of orientation and extent, said first and second pluralities cooperating to form evacuation paths.
Another embodiment of the invention is a method of protecting an object. The method comprises placing the object into a container, the container comprising first and second panels, each defining inner and outer surfaces, joined together to form a package for placing a product therein, each of said first and second panels further comprising a gas-impermeable, heat sealable material, a first plurality of channels on an inner surface of said first panel, and a second plurality of channels on an inner surface of said second panel. The method also includes evacuating the container and sealing the container using said first and second heat-sealable layers.
Another embodiment of the invention is a method for manufacturing a sealing material. The method comprises placing a first film of a gas-impermeable material and placing a second film of a heat-sealable material. The method then comprises adhering the first film to the second film with a layer of adhesive material to form a sealing material. The method then comprises forming channels on the material, said channels forming a network on said material.
Another embodiment is a container of a type comprising first and second rectangular gas-impermeable panels, each defining inner and outer surfaces and both panels sealingly joined together at three common adjacent peripheral edges and not joined at a fourth peripheral edge. Joining the panels forms a gas-impermeable container having an interior chamber and an open edge for placing a product therethrough and into the interior chamber. An improvement to the container comprises a first network of non-interconnected channels on the inner surface of the first panel and a second network of non-interconnected channels on the inner surface of the second panel, wherein said channels of said first network communicate with said channels of said second network when the first and second panels are joined, to form a master network of interconnected channels in communication with the open edge to allow gas to be withdrawn therethrough from the interior of the container.